SON (Self Organizing Network) technology is employed in LTE (Long Term Evolution) which is standardized by the 3GPP (3rd Generation Partnership Project) as a radio communication system standardization organization. SON technology enables a radio base station itself to change the settings of the radio base station without human intervention.
One aspect of SON technology is an energy saving technique (see Non-patent Document 1). The energy saving technique is a technique which changes the mode of a radio base station to the power consumption saving mode (hereinafter, inactive mode) to save the power consumption of the radio base station.
Using the energy saving technique, a radio base station can notify another radio base station of the change of its mode from the active mode to the inactive mode, and can also request another radio base station to change from the inactive mode to the active mode (see Non-patent Document 2).